Boot for pilot timber pile



g- 1967 J. J. DOUGHERTY BOOT FOR PILOT TIMBER FILE Filed March 9, 1965 INVENTOR. JOHN J, DOUGHERTY WJW FITTORNEY United States Patent ABSTRACT on THE DISCLOSURE A boot for a pilot foundation timber pile having a hollow cylindrical body with a side wall and slightly curved bottom wall for receiving the end of a timber pile, a plurality of axially extending fins along the outer periphery of the side wall and extending below the bottom wall, the bottom wall serving to compact the soil into a supporting pressure bulb, the cylindrical body being substantially the same diameter at the bottom as at the top. stiffening ribs are mounted on the outer surface of the bottom wall and a recess is formed in the center of the bottom wall.

This invention relates to piling and more particularly to an improved boot for a pilot timber pile.

Piles are used to support or to form foundations for structures such as buildings, tanks, bridges, conduits, piers, wharves etc. by driving them into or through the yielding surface strata far enough to obtain a solid support for the principal structure. In driving timber piles for foundations, the ordinary practice is to depend upon friction between the exterior surface of the pile and the soil through which the pile passes to develop its bearing power or suupporting power. The stresses in the earth during such operations are concentrated around the pile.

It is the principal object of the present invention to provide a boot for a pilot timber pile for the end of the pile for reinforcing said end and at the same time forming within the soil through which the pile is driven a highly compressed zone of soil, hereinafter called the bulb of pressure.

Another object of the invention is to provide a boot for a pilot timber pile that increases the tip area of the pile.

A further object is to provide a boot for a pilot timber pile that has the effect of a punch and drill when the pile is being driven.

Still another object of the invention is to provide a boot for the end of a pilot timber pile for augmenting the supporting power of the pile so that it will function as a combined friction and end bearing foundation pile.

Still a further object is to provide an improved boot of this type that is especially well adapted to withstand both tensional and compressional longitudinal force as well as lateral stresses.

Yet another object is to provide a boot for a pilot timber pile with elongated tapered fins that will ensure straight and true driving of the foundation pile.

Yet another object according to a modified form of the invention is to provide a boot for a pilot timber pile with a round bottom wall formed with a central conical shaped recess and with fins projecting laterally from the side wall, the recess and fins cooperating to ensure that the boot and pile move vertically downward without any lateral displacement.

For further comprehension of the invention and of the objects and advantages thereof reference will be had to the following description and accompanying drawings and to the appended claims wherein the novel features are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

FIG. 1 is a front elevational view of a boot for a pilot timber pile according to one form of the invention.

FIG. 2 is a bottom plan view thereof.

FIG. 3 is a vertical sectional view through the center of the boot showing the boot applied to the end of a timber pile.

FIG. 4 is a view similar to FIG. 3 showing a modified form of boot.

FIG. 5 is a top plan view thereof.

Referring now in detail to the various views of the drawing, a boot for a pilot timber pile made in accordance with one form of the invention is shown in FIG. 1 and is designated generally by the reference numeral 10. The boot is made of malleable iron and has a cylindrical hollow body with a side wall 12 slightly tapering downwardly and inwardly and terminating in a slightly curved bottom wall 14. The top of the body is open so that the side and bottom wall define a socket opening for supporting the bottom end of a pilot timber pile 16.

On the outer surface of the side wall 12 there are a number of radial fins 18 formed integrally with the side wall. Four fins 18 are shown and each comprises a thin plate formed integrally with the side wall. Each plate is of substantially triangular shape with the apical end 20 at the top edge of the side wall 12 and with the broad base 22 at the bottom edge of the side wall tapering downwardly from the inner end thereof and terminating in a point 24 disposed in a plane below the plane of the lowermost point of the bottom wall 14.

It will be noted that the bottom wall 14 is round and in accordance with the invention intersecting cross ribs 26 are formed on the outer surface thereof.

In use, the boot 10 is easily applied to the bottom of the pile 16. When the pile with the boot thereon is driven, the points 24 of the fins 18 initially penetrate the ground followed by the ribs 26 and then by the round bottom wall 14. The round bottom wall in contacting the soil directly below the tip of pile compacts the soil thereat, the compacted soil assuming an oval shape and creating a pressure bulb. This pressure bulb is cohesionless material, such as sand and gravel, extends part way up the pile shaft. In impervious or cohesive soils, such as clay or silt, the pressure bulb is confined more to the tip area. The load-carrying capacity of the pile is increased by this phenomenon. The ribs 26 reinforce the bottom wall 14.

The fins 18 impart straight and true characteristics to the pile. In the driving operation, the fins act as a drill penetrating heavy layers of dense material such as coarse sand, hardpan or decomposed rock. Boulders, depending on their size and the material upon which they rest are usually broken or pushed aside by the boot.

In FIGS. 4 and 5, a modified form of boot 10 is shown. The boot 10' differs from the boot 10 merely in that a conical shaped recess 28 that may also be of truncated 3 form if desired, is formed in the center of the bottom Wall 14'. This recess 28 coacts with the fins 18 in ensuring that the boot and pile move vertically downwardly without any lateral displacement.

In all other respects, boot 10' is similar to boot 10 and similar reference numerals are used to indicate similar par-ts.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that changes in details of construction might be made Without departing from the principle of the invention and I desire to be limited only by the state of the prior art and the appended claim.

I claim:

A boot for a pilot foundation timber pile comprising a hollow substantially cylindrical body having a side Wall and a slightly curved bottom wall defining a socket for receiving and supporting the end of a timber pile inserted close to said bottom wall, said bottom wall being uniform in cross-section, the juncture of said side and bottom walls constituting a seat for the bottom end of the pile, a plurality of axially extending fins positioned symmetrically along the outer periphery of the side wall and extending slightly below the plane of the bottom wall, said slightly curved bottom wall serving to compact the soil into a supporting pressure bulb, said cylindrical body being of substantially the same diameter at the bottom as at the top, and a conical recess in the center of the bottom wall for guiding the pile downwardly without lateral displacement.

References Cited UNITED STATES PATENTS 1,909,352 5/ 1933 Hausler et al. 17522 2,562,860 7/1951 Cobi 61'53 2,864,241 12/1958 Fiore et al 61-53 FOREIGN PATENTS 67,378 1914 Switzerland.

DAVID J. WILLIAMOWSKY, Primary Examiner.

JACOB SHAPIRO, Examiner. 

